Metal Detectors Useless in Finding Powerful Explosive PETN

The man who authorities say strapped a highly powerful explosive to his torso and tried to detonate it in midair never would have gotten aboard the plane if a different security detector had been used when he boarded the flight, security experts and officials say.

"Puffer" machines, full-body imaging scanners, a simple frisk or bomb-sniffing dogs all would likely have detected the chemical explosive PETN, experts say. But Umar Farouk Abdulmutallab, the 23-year-old Nigerian suspected of trying to blow up Northwest Flight 253 on Christmas Day, encountered none of those deterrents when he traveled from Nigeria to Amsterdam and ultimately to Detroit.

Abdulmutallab may likely have passed through a magnetometer, the conventional metal detector used at most airports. It's a sophisticated device that detects firearms, box-cutters, belt buckles and nail clippers — but it's useless in finding a small amount of powder capable of bringing down an airliner packed with passengers.

PETN is the primary ingredient in detonating cords used for industrial explosions and can be collected by scraping the insides of the wire, said James Crippin, a Colorado explosives expert. Used in military devices and readily found in blasting caps, the chemical is stable and safe to handle but requires a primary explosive to detonate it.

PETN was a component of the explosive that Richard Reid — the convicted "shoe bomber" — used in 2001 in his failed attempt to down an airliner. It also was used in an assassination attempt on the Saudi counterterrorism operations chief in August, according to the Saudi government.

Authorities say Abdulmutallab hid a quantity of PETN in a condom-like bag just below his torso when he boarded the plane in Amsterdam, and that he tried to create an explosion on board by injecting a liquid into it with a syringe.

"Puffer" machines — which release several "puffs" of air to shake loose trace explosive particles on a passenger — are designed to detect chemicals like PETN, but U.S. officials have begun phasing out the machines they require frequent maintenance.

A spokeswoman for the Transportation Security Administration was unable to provide figures on exactly how many "puffer" machines — Explosive Trace Portals (ETPs) — are currently in use in the United States and at what cost. But according to a TSA blog post from May, a total of 33 ETPs were deployed to 15 airports at the time of the posting.

At the program's peak, 94 of the 207 units purchased by the TSA were deployed to 37 airports. But by the summer of 2008, TSA officials decided to cut back on the technology. In total, the TSA has spent roughly $29.6 million on the "puffer" machines, including $6.2 million on maintenance, since the program began in 2004. That equates to roughly $65,957 total maintenance costs per unit, or about $13,191 per unit per year.

"TSA also determined that more reliable and effective screening technologies have become available since ETPs were first introduced," the blog post read. "For these reasons, TSA has decided to phase out this technology."

Full-body scanners, which create an electronic image of passengers to detect weapons or explosives, are reportedly in use in at least six airports nationwide. The machines use radio waves to peer through clothing and have created privacy concerns for passengers who feel invaded as intimate aspects of their bodies are revealed. Despite last week's incident, a Utah congressman says his push to ban their usage has not changed.

Republican Rep. Jason Chaffetz proposed to ban the machines in legislation that passed the House earlier this year but has since stalled in the Senate.

"It's a difficult balance between protecting our civil liberties and protecting the safety of people on airplanes," Chaffetz told The Salt Lake Tribune. "I believe there's technology out there that can identify bomb-type materials without necessarily, overly invading our privacy."

Chaffetz said other law enforcement tools such as heat sensors could be used as alternatives to the full-body scanners and noted that his bill would ban only primary use of the body imaging machines. Under his bill, screeners would still be able to force a passenger through the machines as a secondary screening tool.

According to reports, those machines have not been in use at the Amsterdam airport where Abdulmutallab originated from last week.

"The [security scans] are still in the test phase," an airport spokeswoman told NRC Handelsblad. "European regulations tell us we can only put people through them on a voluntary basis. And objections have been raised with regards to privacy."

But had other screening methods been deployed — such as "puffer" machines, full-body imaging scanners or a even a simple frisk — the powder would have been detected, said Andrew Thomas, an assistant professor at the University of Akron and editor-in-chief of the Journal of Transportation Security.

"Theoretically, if everything was working well, it probably would have," Thomas told FoxNews.com. "But there's a lot of things that have to fall into place."

Thomas said airport screeners should shift their focus away from so-called "bad items" like knives, guns and explosives and rather concentrate on "bad people" who seek to commit terrorist acts.

"We need technology that helps people do their job, not the other way around," he said. "Threats are human and the response needs to be human with the help of technology."

James Carafano, a senior fellow at the Heritage Foundation, a conservative think tank, said a bomb-sniffing dog would also have likely uncovered the chemical.

"That would've done it," Carafano said. "And there are no privacy issues in any of this stuff. There may be some inconvenience, but in terms of legal privacy protections, that's not really the issue here. The issue here is cost."

Homeland Security Secretary Janet Napolitano said Sunday that Abdulmutallab was on a broad U.S. terrorist watch list but was not designated for special screening measures or placed on a no-fly list because of a dearth of specific information regarding his activities. Had he been subjected to a secondary luggage check in Amsterdam, however, screeners would have likely found trace elements of PETN on his body, Carafano said.

"What we really need to be focusing in is stopping the guy from ever getting to the airport," Carafano said. "There was clearly not enough done to connect the dots. We built a system to beat these guys, but unless we use the system that we built, it's not going to work. Throwing a half million people's name into a hat doesn't mean anything unless you do something with those names."

Abdulmutallab did not go through full-body imaging machines in Nigeria or Amerstam, Rep. Peter King, R-N.Y., the top Republican on the Homeland Security Committee, told The Associated Press.

King, who has been briefed on the investigation, said Amsterdam's airport has had a long reputation for good security while Nigeria's has been more of a concern. Both facilities have body scanners. According to the State Department, the U.S. provided full-body scanners to all four international airports in Nigeria.